Her father was a German interior designer; her mother is Bengali. They separated when she was six years old. Her father died when she was nine. When living in Khairatabad, Hyderabad, Diya Mirza attended the Vidyaranya, a school based on the teachings of Krishnamurti, and later Nasr School, in Kushnuma . Later, she moved to Bhandra, Mumbai.

Diya Mirza won the prestigious Miss Asia Pacific title at the beauty pageant held on 2 December, 2000, in Manila. She is the second Indian contestant to be crowned Miss Asia Pacific and the first in 29 years.

She debuuted with "Rehna Hai Tere Dil Mein". Though the film did not do too well, it marked her arrival in the industry. After that, film offers continued to pour in. She did "Tumko Na Bhool Payenge", "Tehzeeb", "Dum" to name a few. Today she has several films to her credit and one thing rings clear out of it, she has arrived as an actress.